$300 isn't actually cheap when you consider how much the retailers buy the actual springs for from the wholesalers.
BTW, when you see lowering kits going for $300-$450, these are only for the springs. You don't need anything else to lower you car, however it is prefered that you replace you shocks also (especially if your shocks are close to stock).
I lowered my car 1.5" by Dunlop Super Dealers in Moorabbin for $280 including labour. The use King Springs. King Springs are a good quality spring, and this is around the average price, after calling around for quotes. I didn't replace the shocks, because I had heavy duty Monroe shocks in my car neway, and I was told they didn't need replacing, unless of course I wanted to.
The car is fine, the difference in handling, just by lowering it 1.5" is very noticable, looks great, handles great, and one thing I love is the high speed stability. It feels a solid as a rock at high speeds (80-150).
My insurance company, RACV, didn't have a problem with me lowering it by this much, and didn't even raise the price of my premium.
I wouldn't want to lower it any more than what I have, because even at 1.5", i have trouble going over speed bumps, and out of driveways as it is, and I can't even drive into the parking lot of my Milkbar, because the bottom of my car scrapes along the ground. Also a good idea is to take off your mudflaps too, because they can scrape and brake off.
All in all, it's worth it to get it lowered, because one weakness I beleive with the stock EA's is their suspension system. It's like driving a damn boat. I hated it. That's why I got mine lowered straight away after I got it from my parents.
And it looks good too, which helps!
All I need is a nice set of 16" mags, and a decent stereo and I'm happy!